Ionic Compositions and Carbonaceous Matter of PM 2.5 at Ieodo Ocean Research Station

Abstract

The purpose of this study is to determine concentrations and compositions of PM2.5 and their characteristic variations at Ieodo Ocean Research Station in the East China Sea and to examine the influence of air pollutants transported from Asia continents. O3 and meteorological parameters were measured since June 2003 and PM2.5 filter samples were collected from June 2004 to June 2008. In total, 244 samples were analyzed for water soluble ions and carbonaceous compounds. The mean mass concentration of PM2.5 and O3 were 21.8±14.9 μg/m3 and 51.6 ±16.1 ppb, respectively. The average concentrations (mass fractions) of sulfate and ammonium were 6.26 μg/m3 (28.74%) and 1.59 μg/m3 (7.31%), respectively. Nitrate was considered to be lost through evaporation due to long stay at the station. The mean concentrations of EC and OC were 1.01 μg/m3 and 2.34 μg/m3, respectively, from June 2006 to June 2008. The average OC/EC ratio was 2.31. The organic matter converted from OC by multiplying 2.1 and elemental carbon constituted 22.60% and 4.66% of PM2.5 mass, respectively.